Esterification reagent used for measuring hydroxyl value by estolide method, and method for measuring hydroxyl value

A technology of acid anhydride and hydroxyl value, which is applied in the direction of chemical analysis by titration method, analysis by making materials undergo chemical reactions, and material analysis by observing the influence on chemical indicators, etc., which can solve the problems of inconvenient operation of analysis tests

Active Publication Date: 2009-05-13
IND TECH RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Due to the special unpleasant odor of pyridine, there are many inconveniences in the operation of analytical tests

Method used

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  • Esterification reagent used for measuring hydroxyl value by estolide method, and method for measuring hydroxyl value
  • Esterification reagent used for measuring hydroxyl value by estolide method, and method for measuring hydroxyl value
  • Esterification reagent used for measuring hydroxyl value by estolide method, and method for measuring hydroxyl value

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Preparation of Esterification Reagent for Measuring Polyol Hydroxyl Value

[0030] Esterification reagents are prepared according to known methods excluding atmospheric humidity. Use reagent grade chemicals.

[0031] Esterification reagent A: at room temperature, 2.0 g of MoO 2 (acac) 2 (6 mmol) was dissolved in 50 g of acetic anhydride (490 mmol) with magnetic stirring to prepare a solution. Afterwards, the above solution was transferred to a 100 ml measuring bottle, and diluted to the marked line with toluene under sufficient shaking. Store this esterification reagent A in a brown bottle.

[0032] Esterification reagent B: at room temperature, 1.3 grams of VO(OAc) 2 (6.6 mmol) was dissolved in 64 g of propionic anhydride (492 mmol) with magnetic stirring to prepare a solution. Afterwards, the above solution was transferred to a 100 ml measuring bottle, and diluted to the marked line with xylene under sufficient shaking. Store this esterification reagent B in a ...

Embodiment 2

[0045] Measure the hydroxyl value of commercial nonionic surfactant polyoxyethylenenonylphenyl ether (theoretical hydroxyl value is 75)

[0046]

[0047] n=12

[0048] First, 2.0115 grams and 2.022 grams of samples were measured and placed in flask 1 and flask 2, respectively. Then, each 5 milliliters of esterification reagent A was dripped into each sample to be tested and the flask used as blank measurement. The titration result of flask 1 is that 37.9 ml of 0.5N sodium hydroxide standard titration solution is consumed, and flask 2 also consumes 37.9 ml. The titration result of the blank test flask 1 is 43.3 milliliters of 0.5 N sodium hydroxide standard titration solution consumed, and the blank test flask 2 consumes 43.5 milliliters, so the average consumption of the blank test is 43.4 milliliters. The concentration (mol / L) of sodium hydroxide standard titration solution is 0.5015. According to the above formula, the hydroxyl value of the sample in flask 1 is calcula...

Embodiment 3

[0050] Measure the hydroxyl value of commercial poly(tetramethylene glycol) (marked hydroxyl value 107.8)

[0051]

[0052] n=14

[0053] First, 1.5514 grams and 1.5453 grams of samples were measured and placed in flask 1 and flask 2, respectively. Then, 5 milliliters of the esterification reagent B was dripped into each sample to be tested and the flask used as a blank measurement. The titration result of flask 1 was 38.1 ml of 0.5N sodium hydroxide standard titration solution consumed, and 38.3 ml of flask 2 was consumed. The titration result of the blank test flask 1 is the consumption of 44.2 milliliters of 0.5N sodium hydroxide standard titration solution, and the blank test flask 2 also consumes 44.2 milliliters, so the average consumption of the blank test is 44.2 milliliters. The concentration (mol / L) of sodium hydroxide standard titration solution is 0.4895. According to the above formula, the hydroxyl value of the sample in flask 1 is calculated to be 108.0, an...

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Abstract

The invention provides a pyridineless esterifying reagent which is used in anhydrides method for measuring polylol hydroxyl values. The reagent comprises anhydrides, an oxygen-metal complex with a formula of MomLn and a solvent of neutrality or subacidity, wherein, M includes a transition metal of IVB group, VB group or VIB group; L includes (OTf), X and the molecular formula; m and n are integers equal to or greater than 1, wherein, X is halogen; R, R', R'' and R''' are respectively alkyl, aryl or heterocyclic radical containing nitrogen, oxygen and phosphorus or sulfur. The invention also provides a method for measuring the polylol hydroxyl values.

Description

【Technical field】 [0001] The invention relates to an esterification reagent for measuring the hydroxyl value of polyols by an acid anhydride method, in particular to a pyridine-free esterification reagent for measuring the hydroxyl value of polyols by an acid anhydride method. 【Background technique】 [0002] The article "Plastics-Polyols for use in the production ofpolyurethane-Determination of hydroxyl number" of ISO 14900:2001(E) discloses the acetic anhydride or phthalic anhydride method currently available for determining the hydroxyl value of polyethers and polyesters. However, these methods have the serious disadvantage of having to use pyridine to dissolve hydroxyl-containing samples. Pyridine is a poisonous and smelly chemical solvent that is harmful to the eyes, nose, throat and skin. It is listed as a level 4 extremely toxic substance in the Hazard Classification Table. [0003] According to the following reaction formula, the hydroxyl-containing macromolecule und...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N31/16G01N21/78
Inventor 林志坚陈建添
Owner IND TECH RES INST
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